The present invention generally relates to a cantilever for an atomic force microscope (AFM) and its manufacturing method, and more particularly relates to a cantilever for the AFM which is provided with a probe having a small radius of curvature at its distal end and a large aspect ratio and its manufacturing method.
In recent years, the AFM has been developed as an apparatus capable of observing the surface of a solid surface on the order of the size of atoms. As shown in FIG. 1, a probe 17 is provided on a cantilever body 18 having a length of 100-200 .mu.m in the known AFM. As described in "Journal of Vacuum Science and Technology", A8, pages 3386-3396, (1990), it has been a general practice that an edge portion at a distal end of the cantilever body is employed as the probe. The probe is manufactured by using an etching pit of crystals as a mold or the probe is manufactured by anisotropic etching. Resolution of the AFM depends upon the radius of curvature at the distal end of the probe, and rises further as the radius of curvature becomes smaller. A probe having a radius of curvature of 20 to 30 nm is manufactured at present and an image of atoms such as mica can be observed by using a cantilever provided with such a probe.
However, the AFM is used not only for observing the surface of a sample on the order of the size of atoms but for observing on the order of nanometers or micrometers a sample having large uneven portions. In the case of the latter observation of a sample, especially, with a sample having deep pits such as grating the probe 17 cannot reach bottom of the pits, and thus it is difficult to accurately measure the shape of the pits. Thus, in this case there is a keen demand for a cantilever provided with a probe which not only has a small radius of curvature at its distal end but has an elongated shape enabling the probe to reach bottom of the pits.